A WAN is a collection of two or more LANs network whose elements may be separated by distances great enough to require telephone communications. The WAN supports communications between such elements. For most WANs, the long-distance bandwidth is relatively slow, on the order of kilobits per second kbps) as opposed to megabits per second (Mbps) for LANs. There is no specified upper limit to the radius of a WAN, but in practice, computers distributed over areas larger than a state almost certainly belong to different networks that are connected to each other. Such a setup is known as Wide-Area Internetworks (WAI).